Trial of RA Drug Halted

Isis Pharmaceuticals is halting development of a new treatment for rheumatoid arthritis that targets the inflammatory marker C-reactive protein (CRP) for lack of clinical benefits, the company announced Monday.

In a phase II randomized study that included 51 patients with active rheumatoid arthritis of at least 6 months' duration, there were rapid, dose-dependent decreases in CRP levels of up to 67%.

These decreases were accompanied by improvements in rheumatoid arthritis signs and symptoms as measured on the American College of Rheumatology criteria, but the differences weren't statistically different from placebo.

Patients randomized to receive placebo showed "a higher than expected response in both symptom score and CRP reduction," the company said in a press release.

"We are pleased with the consistency of CRP lowering across all of our clinical studies, but we are disappointed that we did not see a greater impact on [rheumatoid arthritis] symptoms in these patients," said Isis senior vice president Richard Geary, PhD, in the statement to the press.

The study, conducted in Canada and Russia, tested ISIS-CRP at doses of 100, 200, or 400 mg per day for 3 months.

Participants also were taking methotrexate in dosages of at least 10 mg per week, and could be on corticosteroids with average daily doses of 10 mg.

The drug was developed using antisense technology that targets RNA.

It is also being evaluated in a phase II study for patients with atrial fibrillation.

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